Staff: Mentor

Do you mean ##u^2## and ##v^2##, with the 2 small and high? In that case, it is called an exponent and, in the present case, means "squared":
$$
u^2 = u \times u
$$
and
$$
v^5 = v \times v \times v \times v \times v
$$
You can have a look at Wikipedia for what it means when the exponent is not a positive integer.

Multiplication is used so much in maths that it's simply much easier to get rid of the [itex]\times[/itex] symbol. This also meant that the letter [itex]x[/itex] could be used as a variable (and it's used a lot) without running into problems of ambiguity between it being a variable or a multiplication symbol.

Whenever you have a situation like [itex]2\times 5[/itex] then you're expected to evaluate that to 10, while [itex]2\times a=2a[/itex] cannot be simplified further so it's ok to leave as it is.